this is what I used (I found this on rctech a while back):
Since first running my B4 in April 2003, I have cracked numerous sets of Proline B4 front wheels. Myself and a lot of others that run a B4 at our track (CRCRC) have cracked the front, and some rear, Proline Wheels.
I have also heard complaints about the Proline front wheels not being true.
I have been running Losi rear wheels. No mod needed.
Today I ran Losi front wheels.
To complete this mod:
Losi A-1122 Front Spindle and Carrier
Losi A-1133 Front Stub Axles and Screws
Losi A-3016 Axle Spacers
7/64 Drill Bit
1) Drill out the hinge pin hole in both Losi Spindles with a 7/64 Drill Bit
2) Remove Left and Right Associated B4 Spindles
3) Assemble Losi Spindles: insert bearings, axle, spacer, and screw
4) Install Losi Spindles onto the B4 in place of the Associated Spindles; no spacers; Losi spindle fits directly in the Associated carrier. (Spindle could be modified to allow up/down positions by taking material off the top and bottom of the spindle and then using spacers)
5) Use one washer underneath the ball stud on the spindle. Install ball stud in spindle in same orientation as the stock B4. Use a locknut to secure the ball stud to the spindle.
6) Install wheels and tires
7) Set Steering EPA on radio
I ran this today (02/15/2004). I noticed no decrease in performance. My lap times were actually faster than last week. This mod may not be performance improving, but I donít believe that it has any negative effect on the B4ís handling.
The car maintains the same width as the stock spindle B4. It is within ROAR width limits.
ALL TAMIYA 4 WHEEL DRIVE ALL THE TIME
TRF-416X, SP CIRTIX, LRP X-12 17.5, FUTABA 9550